Purpose: To examine the type of orbital blowout fracture and its variation with race.
Design: Retrospective review of computed tomography (CT) scans and demography in an unselected cohort of patients with orbital blowout fractures.
Participants: Patients with a high-resolution CT scan of adequate quality for analysis who presented with an orbital blowout fracture to the Orbital Clinic at Moorfields Eye Hospital. Patients with fractures involving the orbital rim or the cranium, or with penetrating injuries of the globe or orbit, were omitted from the study.
Methods: Demographic and ethnic information was collected for each patient, and the orbital scans were reviewed by a single observer. On the basis of coronal and axial imaging, a fracture was classified as affecting up to 4 areas: the floor lateral to the infraorbital canal (area 1, "A1"), the floor medial to the canal ("A2"), the maxillo-ethmoidal strut ("inferomedial" strut, "A3"), and the medial wall blowout fracture ("A4"); with fractures involving the inferomedial strut, it was noted whether there was displacement or rotation of the strut. Ethnic origin was classified as Caucasian, Afro-Caribbean, or Asian (Oriental or Indian).
Main outcome measures: The proportion of different walls involved in orbital blowout fractures within 3 ethnic groups.
Results: A total of 152 patients (125 men, 82%) had imaging adequate for analysis; 103 (68%) were Caucasian, 19 (12%) were Afro-Caribbean, and 30 (20%) were Asian. Caucasians most commonly had floor fractures (A1 or A2 in 56 orbits, 54%) compared with 10 of 103 purely medial fractures (A4, 10%); in contrast, medial fractures were the most common type in Afro-Caribbean patients (7/19 cases, 37%), and purely floor fractures occurred in only 2 cases (10%) (P<0.005). Asian patients had results similar to those for Caucasian patients, with isolated floor fractures being the most common (14/30 cases, 47%).
Conclusions: Most blowout fractures involve the orbital floor in Caucasian and Asians, whereas in Afro-Caribbeans the most common site for fracture is the medial wall.
Financial disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Copyright © 2011 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.